1. Field of the Invention
The present invention relates to an organic light emitting display (OLED) device with low drive voltage and high luminous efficiency, and a method for manufacturing the same.
2. Discussion of the Related Art
In line with recent developments in information era, there has been rapid advancement in the display field. To meet such development, various flat panel display devices with excellent performance, such as ultra-thin thickness, lightweight and low power consumption, have been developed.
Examples of flat panel display devices include, without limitation, liquid crystal display (LCD) devices, plasma display panel (PDP) devices, field emission display (FED) devices, and organic light emitting display (OLED) devices.
In particular, OLED devices, which are a self-emissive device, have faster response time, higher luminous efficiency, higher luminance and wider viewing angle compared with other flat panel display devices. OLED devices typically include an anode, a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, an electron injection layer, and a cathode.
OLED devices typically have a single light emitting unit structure including a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, and an electron injection layer disposed between first and second electrodes. In recent years, however, OLED devices having a multi-light emitting unit structure including a plurality of light emitting units disposed between first and second electrodes have been developed.
In the conventional multi-light emitting unit structure, a plurality of organic layers are provided between the first and second electrodes, which leads to an increased drive voltage. In addition, OLED device having the conventional multi-light emitting unit structure may not provide luminous efficiency proportional to the number of the light emitting layers as compared with OLED devices having a single light emitting unit structure.